ksmbd: make utf-8 file name comparison work in __caseless_lookup()

Case-insensitive file name lookups with __caseless_lookup() use
strncasecmp() for file name comparison. strncasecmp() assumes an
ISO8859-1-compatible encoding, which is not the case here as UTF-8
is always used. As such, use of strncasecmp() here produces correct
results only if both strings use characters in the ASCII range only.
Fix this by using utf8_strncasecmp() if CONFIG_UNICODE is set. On
failure or if CONFIG_UNICODE is not set, fallback to strncasecmp().
Also, as we are adding an include for `linux/unicode.h', include it
in `fs/ksmbd/connection.h' as well since it should be explicit there.

Signed-off-by: Atte Heikkilä <atteh.mailbox@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/ksmbd/connection.h b/fs/ksmbd/connection.h
index 41d96f5..3643354 100644 (file)
--- a/fs/ksmbd/connection.h
+++ b/fs/ksmbd/connection.h
@@ -14,6 +14,7 @@
 #include <net/request_sock.h>
 #include <linux/kthread.h>
 #include <linux/nls.h>
+#include <linux/unicode.h>
 
 #include "smb_common.h"
 #include "ksmbd_work.h"

diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index 4fcf96a..8d8af72 100644 (file)
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -1145,12 +1145,23 @@ static int __caseless_lookup(struct dir_context *ctx, const char *name,
                             unsigned int d_type)
 {
        struct ksmbd_readdir_data *buf;
+       int cmp = -EINVAL;
 
        buf = container_of(ctx, struct ksmbd_readdir_data, ctx);
 
        if (buf->used != namlen)
                return 0;
-       if (!strncasecmp((char *)buf->private, name, namlen)) {
+       if (IS_ENABLED(CONFIG_UNICODE) && buf->um) {
+               const struct qstr q_buf = {.name = buf->private,
+                                          .len = buf->used};
+               const struct qstr q_name = {.name = name,
+                                           .len = namlen};
+
+               cmp = utf8_strncasecmp(buf->um, &q_buf, &q_name);
+       }
+       if (cmp < 0)
+               cmp = strncasecmp((char *)buf->private, name, namlen);
+       if (!cmp) {
                memcpy((char *)buf->private, name, namlen);
                buf->dirent_count = 1;
                return -EEXIST;
@@ -1166,7 +1177,8 @@ static int __caseless_lookup(struct dir_context *ctx, const char *name,
  *
  * Return:     0 on success, otherwise error
  */
-static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, size_t namelen)
+static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name,
+                                  size_t namelen, struct unicode_map *um)
 {
        int ret;
        struct file *dfilp;
@@ -1176,6 +1188,7 @@ static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, size_t na
                .private        = name,
                .used           = namelen,
                .dirent_count   = 0,
+               .um             = um,
        };
 
        dfilp = dentry_open(dir, flags, current_cred());
@@ -1238,7 +1251,8 @@ int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *name,
                                break;
 
                        err = ksmbd_vfs_lookup_in_dir(&parent, filename,
-                                                     filename_len);
+                                                     filename_len,
+                                                     work->conn->um);
                        path_put(&parent);
                        if (err)
                                goto out;

diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h
index d7542a2..593059c 100644 (file)
--- a/fs/ksmbd/vfs.h
+++ b/fs/ksmbd/vfs.h
@@ -12,6 +12,7 @@
 #include <linux/namei.h>
 #include <uapi/linux/xattr.h>
 #include <linux/posix_acl.h>
+#include <linux/unicode.h>
 
 #include "smbacl.h"
 #include "xattr.h"
@@ -60,6 +61,7 @@ struct ksmbd_readdir_data {
        unsigned int            used;
        unsigned int            dirent_count;
        unsigned int            file_attr;
+       struct unicode_map      *um;
 };
 
 /* ksmbd kstat wrapper to get valid create time when reading dir entry */